Give me a clue

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Across
  1. 3. An object, which is often made by an inventor, that
  2. 4. A relative pronoun
  3. 7. An article
  4. 8. A verb
  5. 9. A modal verb
  6. 10. A person who
  7. 13. a form of
  8. 15. A verb
  9. 16. An article
Down
  1. 1. A negative modal verb that
  2. 2. university A place where students can earn degrees.
  3. 4. A relative pronoun
  4. 5. very hard clue
  5. 6. A person who works in schools and helps students learn.
  6. 11. a rock that comes from space
  7. 12. Something which is not handmande
  8. 14. A word which